There is disclosed in U.S. Pat. No. 4,745,264, assigned to the same assignee as the present invention, a Curie point self-regulating soldering iron employing a constant current supply to a coil that is flux coupled to a high mu material forming a layer on a copper rod extending rearwardly from the tip of the iron. The commercial embodiment of the constant current supply operates at 13.56 megahertz and is quite expensive.
As disclosed in the aforesaid patent and U.S. Pat. No. 4,839,501, of one of the present inventors, the soldering iron under discussion is comprised of a handle and a cartridge insertable into the handle. The cartridge essentially comprises the heater structure including the coil, the high mu material and the tip of the iron. Electrical connection between the cartridge and a cable coming into the handle from the power supply is made upon insertion of the cartridge into the handle.
The cartridges are also expensive but the use of insertable cartridges is justified to permit interchange of cartridges that operate at different temperatures as well as providing different tip faces. Specifically the temperature at which a cartridge self-regulates is a function of the high permeability material employed.